These systems comprise a steering member, such as for example a steering wheel or helm, whose rotation causes the corresponding rotation of a drive shaft of a control pulse or signal generating device which is typically housed in a case from which said drive shaft protrudes and that by means of a transmission circuit, transmits the generated pulses or signals corresponding to the rotational motion of the shaft to an actuator, associated with the motor and/or rudder or other units that change the direction of a watercraft.
In hydraulic systems, the rotation of the drive shaft causes a displacement of a pressurized fluid, in one direction or in the opposite direction, depending on the rotation of the steering wheel and which fluid is supplied to a hydraulic cylinder through a hydraulic circuit.
The pressurized fluid is supplied by a system of distributor valves to each one of the two ports respectively of a double-acting hydraulic cylinder that, therefore, moves along a rod, kept stationary between two fixed points connected to its ends, in a direction or in the opposite direction depending on the rotational direction of the drive shaft of the pump. The cylinder is in turn connected by means of linkages to a steering arm, for example of a marine outboard motor or to a control lever of a rudder.
In mechanical systems, the pump is replaced by rotary or rectilinear mechanical steering systems which move one or two steel cables, which is/are connected by linkages to a steering control element, which is moved in one or the other opposite direction depending on the direction of rotation of the drive shaft of the steering systems.
In electric/electronic systems the rotation of the drive shaft is read by electromechanical, electronic, magnetic, optical transducers or by combinations of such transducers which generate electromagnetic or possibly also optical signals uniquely related to the angle position and the direction of rotation of the drive shaft.
An electronic control unit manages communications among the several components of the watercraft through communication lines, with a predetermined protocol for coding and transmitting signals, such as for example bus called as CAN-BUS, and interprets and recognizes the signals of the several control members while generating in turn signals operating relevant actuators connected to the members to be controlled, specifically a rudder or an outboard motor.
Electromechanical systems are in the middle between electric and mechanical systems since provide the steering to be always of the mechanical type, that is by tie rods, but using servomechanisms to limit the effort exerted by the user.
Whatever system is used, the components transmitting the motion of the drive shaft are generally housed in a cabinet or compartment placed under the bridge. The control signal or pulse generating device can be arranged with its case at least partially embedded in the bridge or completely embedded in the compartment of the bridge, with the shaft protruding out therefrom for the connection to the wheel.
In known systems, the shaft has a precise inclination with respect to the surface of the bridge such that driving is made comfortable.
However there is the need of changing the tilt angle of the wheel depending on driving characteristics. To this end solutions have been suggested that use a universal joint coupling the hub of the steering wheel or helm to the drive shaft according to variable directions thus realizing the so called tilt of the steering wheel or helm.
Therefore the joint of known solutions is interposed between the drive shaft and the steering wheel and it causes not only the distance between the steering wheel and the bridge to be extended, since the universal joint is a kind of extension of the drive shaft, but it also generates, due to the possibility of tilting the output axis and the input axis with each other, elbows that make uncomfortable to turn the wheel, since the hub of the steering wheel is not more centered with the drive shaft and since the axis of the hub of the steering wheel and the one of the shaft are not more aligned with each other.
Moreover, although such solutions accomplish their functions even if with the above mentioned restrictions, they also have the drawback of requiring an additional component (the universal joint) to be fitted on the dashboard between the drive shaft and the steering wheel with the case of the transmission member completely arranged underneath the bridge. This leads to considerable encumbrance both on the part above the bridge, due to the presence of the universal joint, and also under the bridge where the case of the transmission member is completely housed.